In recent years, touch sensor panels, touch screens, and the like have become available as input devices. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a touch sensor panel, which can be a clear panel with a touch-sensitive surface, and a display device, such as an LCD panel, that can be positioned partially or fully behind the touch sensor panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. Touch screens can allow a user to perform various functions by touching the touch sensor panel using a finger, stylus or other object at a location often dictated by a user interface (UI) being displayed by the display device. In general, touch screens can recognize a touch event and the position of the touch event on the touch sensor panel, and a computing system can then interpret the touch event in accordance with the display appearing at the time of the touch event, and thereafter can perform one or more actions based on the touch event.
Touch sensor panels can include an array of touch sensors capable of detecting touch events (the touching by an object such as a finger upon a touch-sensitive surface). Some current touch panels are able to detect multiple touches (e.g., the touching of multiple fingers upon a touch-sensitive surface at distinct locations at about the same time) and near touches (e.g., fingers within the near-field detection capabilities of their touch sensors), and identify and track their locations. However, in some touch sensing technologies such as projection-scan touch sensing, the location of multiple touches cannot be unambiguously determined.